Ought it not be a terror to us, to cut off a lap of Christ’s garment, or clip it so short, as to think that it cannot cover us completely, without some rags of our own rotten righteousness sewed into it?
Again, it is this legal principle, that makes believers themselves think it cannot be that they are accepted as righteous, perfectly righteous in the sight of God, through the righteousness of Christ imputed; why, because they want a feeling of that righteousness in themselves, which the legal heart is ready to make the foundation of pardon and acceptance: But as Luther said, we must not feel, but believe, that we are thus righteous; yea, it is his hidden principle of self righteousness, that will make a minister preach Christ alone for righteousness, as if he were as much for exalting Christ, as any that ever preached; and yet, before ever you know well where you are, you will find him bringing in some legal duty of qualification, in order to your being justified.”
Ralph Erskine (1685–1752), Sermon on Matthew 22:42 in A Collection of Sermons on Several Subjects preached by the Rev. Ralph Erskine, minister of the Gospel in Scotland and author of the Gospel Sonnets, 78. (HT: Inwoo Lee)
I think another subtly bringing in works is to make repentence into an exercise in such a focus on sin and it’s depravity that the righteousness of Christ is forgotten. We must indeed acknowledge and turn from our sins, but believers only need their feet washed, not a complete bathing (John 13:10).
You make an excellent point, I think the confusion is in making our response to God’s grace, our sanctification, necessary for justification and acceptance before God, or doing our part. That’s the subtle lie of moralism, that if repentance and good works are the evidence of true faith, they must be part of what justifies us, so we better get doing! Belgic 24 says it so well. We must be justified before we can do any good works. True faith relies only in the righteousness of Christ, for salvation. It therefore responds in love and gratitude for what has been received, not to secure acceptance. True faith never looks to itself, it is focused on its Saviour, so it wants to please Him by obeying Him.
One of those ways of bringing in such a legal duty is to make our faith the condition of justification. “Instead faith is God’s work in us, that changes us and gives us a new birth from God. It kills the old Adam and makes us into completely different people. It changes our hearts, our spirits, our thoughts and all our powers. It brings the Holy Spirit with it.” Martin Luther introduction to Romans. It gets its effectiveness from looking to Christ as its object, and God as it’s source, not in looking to our faith as the one condition we must meet.
“What makes you think God will accept your rotten, stinking righteousness?” Martin Luther
I love this quote.